The Arabidopsis RFC1 Gene is Required for Interference-Sensitive Meiotic Crossover Formation

Meiotic recombination is crucial for normal meiotic homolog association and segregation, thereby ensuring normal fertility in plants and other eukaryotes. In addition, meiotic recombination redistributes genome variations and affects allelic frequencies each generation. We have identified and characterized several Arabidopsis genes important for meiotic recombination using molecular genetics. To identify additional genes potentially important for meiotic recombination and other meiotic functions, we analyzed Arabidopsis male meiocyte transcriptome using high throughput sequencing of cDNAs and detected the expression of ~16,000 genes. Among the genes detected in Arabidopsis meiocytes are those similar to genes for recombination, DNA repair or DNA synthesis, suggesting that they might be involved in meiotic recombination. In particular, DNA synthesis genes have not been extensively studied for their roles in meiosis because they are essential for the mitotic DNA replication and mutations in them tend to be lethal. We have used molecular and cell biological approaches to study the function of several genes involved in DNA synthesis, and we have found that the DNA replication factor RFC1 is required for normal meiotic recombination. Specifically it is important for the interference-sensitive pathway of crossing over. Genetic analyses with other known meiotic mutations further support this hypothesis. Other experiments currently under way and the implications of our findings will be discussed.